Trichloroethylene (TCE) has taken a bad rap as of late. But, is it justified knowing all the other hazardous chemicals used much more often? In the writer’s immediate area–1 mile from a CTS electroplating site—which was shut down in 1986 (23 years ago). It has been labeled a Superfund RCRA Site due to trichloroethylene groundwater contamination. Maybe our houses should be labeled Superfund Sites as well.
Most chemical sites receive the Superfund label if they have disposed of hazardous chemicals improperly. Those chemicals are also flammable, toxic, or corrosive. But if one takes a normal hairspray that usually contains dimethyl ether (DME) as a propellant, one must think about the typical breathing amounts inhaled.
A typical dose of DME usually exceeds breathing at least 500 parts per million (ppm) for the person applying the hairspray—that’s 0.05 volume % for a short period of time. The Material Safety Data Sheet reveals that for a mouse, the lethal concentration for a 15 minute interval with DME is 386ppm. We also know the flash point of DME to be minus 41oC—the temperature at which it will ignite by having a small flame available. We just have to remember never to hairspray for longer than 15 minutes, or to have a small flame in the room.
Other typically used items around the house include gasoline, butane, paint thinner, other aerosols, antifreeze, pesticides, wood preservatives, mercury (lights, paint), spot remover, cyanide compounds (rat fumigants), ant traps, old fire extinguishers, pool chemicals, oven cleaners, battery acid…you name it. All either are flammable, toxic, corrosive, or a combination thereof. But there has yet a household to be labeled a Superfund Site.
Because TCE is listed on its MSDS as ‘reasonably anticipated to be a possible human carcinogen’, millions worried about carcinogenicity, and cancer flags were immediately raised. People living nearby the CTS site became scared for their lives. At a neighborhood meeting at the local fire station on 1/31/08, one fellow even claimed that TCE was responsible for 8 cancer occurrences in his family who lived within a mile of the CTS site.
Because TCE is relatively pervasive in the environment, many people are likely to become exposed by simply breathing, eating, and drinking. Inhalation is the main route of potential exposure, so various people were checked for TCE background levels. But no one tested showed any increase or accumulation of TCE.
EPA’s Contract Laboratory Program Statistical Database reports that TCE supposedly occurs in 3% of surface water samples at an average level of 40.2 ppb, and in 19% of groundwater samples at a concentration of 27.3 ppb. Both are much higher than the Maximum Contaminant Level (MCL).
Locally, with the existing CTS electroplating site, the EPA sampled 66 wells within 1 mile of the CTS site. Only one well exceeded the MCL in that area. The MCL for TCE has been set at 5ppb in 1985, so it was made 2,000 times higher. The media always reports the new MCL, so a few analyses show up as wildly high.
The carcinogenicity of TCE was first evaluated in laboratory animals in 1970. TCE actually but had been used in inhalers 40 years ago as a gas anesthetic with favorable analgesic properties (1% vapor/ 10,000 ppm). Because of these properties, Trilene (TCE) inhalers were frequently used, especially by those about to give birth.
Millions of people have breathed high concentrations of TCE. So far, no human is known to have gotten cancer from TCE. One recent review of the epidemiology of kidney cancer rated cigarette smoking and obesity as more important risk factors for kidney cancer than exposure to solvents such as trichloroethylene.
It seems in the MSDS stating “reasonably anticipated to be a possible human carcinogen”, anticipated could be defined as “expected, but never happened”, and possible could mean “in all the millions of cases of high exposure, we haven’t seen anything yet”.
Several things we should all remember: 1) the concentration of ppm is 1000x more concentrated than ppb, and 2) drinking 10 liters of water over a course of a few minutes has resulted in death.
Other than that, just don’t have your wife spray her hair in a closed room, or while smoking a lit cigarette. TCE is probably dangerous in some way. We know it’s not flammable, radioactive, carcinogenic, toxic, or corrosive. It probably could be listed as #1862 on the ‘most dangerous chemical list’. But where would water be on that list?
Yet someone had the wherewithal to put it on a Superfund Site list and have the government (a.k.a., taxpayer) pay over $15 million to clean up a plant that really poses no risk.
Kevin Roeten can be reached at email@example.com